The increasing channel density and data rates used by switching and/or routing platforms has resulted in a corresponding increase in both the number of switch fabric channels (e.g., Serializer/Deserializer (“SerDes”) channels) and the operating frequency within the platform. This increase has made it harder to provide the desired connector density, signal integrity, and thermal cooling within the platform. One way to solve the connectivity problems is to increase the number of backplane routing layers used to connect the port cards with the switch-fabric cards. However, the increased pin density of the backplane connectors has negated some of the routing improvements and causes signal integrity issues at higher frequencies due to the increased distance data has to travel to route around other connectors.
To mitigate issues with routing in a backplane, some platforms are designed such that the cards are directly connected together orthogonally to each other. The direct connection between the cards avoids routing in the backplane but limits the number of port cards that can be used based on the size that a printed circuit board (PCB) can be manufactured for the switch-fabric cards. The orthogonal architecture also has thermal constraints due to the limited airflow for cooling. Optimum front to rear airflow can not be achieved in part because there are limited open areas through which the air is able to flow. In addition, the air that does flow to the switch-fabric cards is at least partially pre-heated by the port cards, or vice-versa. This thermal constraint may further limit the maximum component density on a card.